The Good: The Cat S60 features a built-in thermal imaging camera. It can consistently survive 6 foot drops onto concrete and can take a 16 foot dunking into water. It has an expandable microSD card slot and loud front-facing speakers. The Bad: It's significantly thicker and heavier than other smartphones. The thermal imaging feature while cool and fun, is mostly useless aside from some specific cases. The Bottom Line: The Cat S60's durable build is impressive, but its appeal is limited to those who can make good use of its built-in thermal imaging camera. The Cat S60 is thick and hefty with an unapologetically industrial design. In addition to being a tough SOB that can endure 6-foot drops and the most waterproof phone made to date, it also has one thing no other phone possesses: a built-in thermal imaging camera. If you have to ask why anyone would need a durable, waterproof phone with a thermal imaging camera, the Cat S60 probably isn't for you. Those of you whose ears perk up at the mention of the phone's features should definitely stick around, however.The phone is available for pre-order in the UK for \u00a3529 unlocked. US and Australian pre-orders have yet to be announced, but the UK price converts to around AU$920. In the US it will sell for $599 unlocked and work with GSM networks like T-Mobile and AT&T.Thermal imaging camera includedA thermal imaging camera gives you superpowers. It allows you to visualize the temperature of objects, like an animal in the dark or frozen pipes. The built-in Flir thermal imaging camera is located on the back of the phone, above the 13-megapixel rear camera and next to the microSD card and SIM slots. It's the same one found on the Flir One thermal camera accessory, which is available for iOS and Android devices for $250 or \u00a3200 (AU$330, converted) -- a bargain considering most thermal imaging cameras cost thousands of dollars.The Flir camera app takes a whopping 10-15 seconds to launch on the S60. The app offers nine different filters (they range in color palette and help make certain temperatures more visible than others) and you can take photos or videos. There's also the Flir Tools app (free in the Android app store) that allows you to see a variety of detailed data attached to the thermal images (like the temperature of a specific spot or the range of temperatures in the photo) after you take them.I enjoyed using the thermal camera to take colorful, trippy photos and psychedelic videos, however I, personally, found little practical use for it. It came in handy when a friend needed to know the accurate temperature of her oven while baking a cheesecake (the temperature markings on the stove's knob had faded) and when I wanted to know if my coffee was cool enough to drink, but that's it. If you're a firefighter, independent contractor or work in construction, you're more likely to come across situations where this type of technology comes in handy.Durable designEven with its smallish 4.7-inch screen, the Cat S60 still feels cumbersome. It's almost twice as thick as the iPhone 6S and tired out my wrist when I held it too long.It's still comfortable to use in short spurts. The smooth, rounded edges afforded it a satisfyingly tactile feel and its buttons are conveniently big and easy to press (like a kids toy). The weaved etching on the back panel also makes it easy to grip and use if your hands are wet or you're wearing gloves.It's IP68 certified and can withstand a 6-foot (1.8m) fall onto concrete and can be submerged up to 16-feet (5m) underwater for up to 60 minutes -- making it the most waterproof phone on the market.I didn't take the Cat S60 diving, but I used every opportunity to get it wet. (I splashed it with water numerous times and dunked it 3-feet underwater for the duration of three Friends episodes.) After a quick towel off, it worked fine every time. Sometimes, if the screen was still a bit wet, my swipes and taps wouldn't be recognized, even though the Gorilla Glass 4 touchscreen is supposed to be "wet finger-compatible." Completely drying the screen fixed the problem.